Imaging assembly for intravascular imaging device and associated devices, systems, and methods

ABSTRACT

A method of assembling an intravascular imaging device ( 102 ) is provided. In one embodiment, the method includes obtaining a support member having a body portion including a plurality of recesses longitudinally spaced from one another ( 405 ); positioning a flex circuit around the support member such that the flex circuit is radially spaced from the body portion of the support member ( 410 ); and filling a space between the flex circuit and the support member with a backing material through the plurality of recesses of the body portion ( 420 ). In one embodiment, an intravascular imaging device includes a flexible elongate member; an imaging assembly including: a flex circuit; and a support member ( 330 ) around which the flex circuit is disposed, the support member having a body portion including plurality of recesses ( 339 ), wherein the support member defines lumen in fluid communication with a space between the flex circuit and the support member via the plurality of recesses.

This application is the U.S. National Phase application under 35 U.S.C.§ 371 of International Application No. PCT/IB2017/051727, filed on Mar.27, 2017, which claims the benefit of Provisional Application Ser. No.62/315,428, filed Mar. 30, 2016. These applications are herebyincorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates generally to intravascular ultrasound(IVUS) imaging and, in particular, to the structure of an intravascularimaging device. For example, the intravascular imaging device caninclude an imaging assembly at a distal portion thereof having a supportmember and a flex circuit positioned around the support member.

BACKGROUND

Intravascular ultrasound (IVUS) imaging is widely used in interventionalcardiology as a diagnostic tool for assessing a diseased vessel, such asan artery, within the human body to determine the need for treatment, toguide the intervention, and/or to assess its effectiveness. An IVUSdevice including one or more ultrasound transducers is passed into thevessel and guided to the area to be imaged. The transducers emitultrasonic energy in order to create an image of the vessel of interest.Ultrasonic waves are partially reflected by discontinuities arising fromtissue structures (such as the various layers of the vessel wall), redblood cells, and other features of interest. Echoes from the reflectedwaves are received by the transducer and passed along to an IVUS imagingsystem. The imaging system processes the received ultrasound echoes toproduce a cross-sectional image of the vessel where the device isplaced.

Solid-state (also known as synthetic-aperture) IVUS catheters are one ofthe two types of IVUS devices commonly used today, the other type beingthe rotational IVUS catheter. Solid-state IVUS catheters carry a scannerassembly that includes an array of ultrasound transducers distributedaround its circumference along with one or more integrated circuitcontroller chips mounted adjacent to the transducer array. Thecontrollers select individual transducer elements (or groups ofelements) for transmitting an ultrasound pulse and for receiving theultrasound echo signal. By stepping through a sequence oftransmit-receive pairs, the solid-state IVUS system can synthesize theeffect of a mechanically scanned ultrasound transducer but withoutmoving parts (hence the solid-state designation). Since there is norotating mechanical element, the transducer array can be placed indirect contact with the blood and vessel tissue with minimal risk ofvessel trauma. Furthermore, because there is no rotating element, theelectrical interface is simplified. The solid-state scanner can be wireddirectly to the imaging system with a simple electrical cable and astandard detachable electrical connector, rather than the complexrotating electrical interface required for a rotational IVUS device.

Manufacturing an intravascular imaging device that can efficientlytraverse physiology within the human body is challenging. In thatregard, components at the distal portion of the imaging device can beassembled in a manner that excessively enlarges an outer diameter, whichmakes navigation through smaller diameter vessels difficult. Ensuringrobust mechanical coupling between components can also be challenging.

Thus, there remains a need for intravascular ultrasound imaging systemthat overcomes the limitations of a large diameter imaging assemblywhile achieving strong and efficient assembly and operation.

SUMMARY

Embodiments of the present disclosure provide an improved intravascularultrasound imaging system for generating images of a blood vessel. Adistal portion of an intravascular imaging device can include a flexcircuit and a support member around which the flex circuit ispositioned. The support member can include longitudinally spacedrecesses. A space between the flex circuit and the support member can befilled with an acoustic backing material that is introduced via therecesses. The flex circuit can include a conductor interface thatextends at an oblique angle relative to a main body of the flex circuit.The conductor interface can advantageously allow for conductors to theelectrically coupled to the flex circuit while minimizing outerdiameter. Lap joints can be used to join flex circuit and proximal anddistal members, which provide strong connections between components. Aproximal portion of the support member can include cavities that allowfor adhesive to effectively bind components at the proximal portion ofthe imaging assembly

In one embodiment, a method of assembling an intravascular imagingdevice is provided. The method includes obtaining a support memberhaving a body portion including a plurality of recesses longitudinallyspaced from one another; positioning a flex circuit around the supportmember such that the flex circuit is radially spaced from the bodyportion of the support member; and filling a space between the flexcircuit and the support member with a backing material through theplurality of recesses of the body portion.

In some embodiments, the support member defines lumen in fluidcommunication with the space between the flex circuit and the supportmember via the plurality of recesses. In some embodiments, the fillingincludes introducing the backing material into the lumen of the supportmember such that the backing material flows into the space between thespace between the flex circuit and the support member via the pluralityof recesses. In some embodiments, the method further includespositioning a mandrel within the lumen before filing the space betweenthe flex circuit and the support member with the blacking material; andremoving the mandrel after the backing material cures. In someembodiments, the method further includes removing excess backingmaterial from the lumen after the backing material cures. In someembodiments, each of the plurality of recesses extends from an outersurface of body portion through an inner surface of the lumen. In someembodiments, the body portion of the support member surrounds the lumen.In some embodiments, the support member includes proximal and distalstands, the body portion extending longitudinally between the proximaland distal stands, and wherein the proximal and distal stands have alarger outer diameter than the body portion. In some embodiments, thepositioning a flex circuit around the support member includes wrappingthe flex circuit in a cylindrical configuration around the supportmember such that the flex circuit is in contact with the proximal anddistal stands and spaced from the body portion of support member. Insome embodiments, the method further includes evacuating air from thespace between the flex circuit and the support member via an opening inat least one of the proximal or distal stands.

In some embodiments, the method further includes coupling a distalmember to at least one of the flex circuit or the support member. Insome embodiments, the flex circuit and the distal member form a lapjoint. In some embodiments, the support member includes a distal flangesized and shaped to facilitate coupling to the distal member. In someembodiments, the method further includes coupling a proximal member toat least one of the flex circuit or the support member. In someembodiments, the flex circuit and the distal member form a lap joint. Insome embodiments, the support member includes a proximal flange having aplurality of cavities, and wherein the coupling a proximal membercomprises: applying an adhesive to affix the proximal member and thesupport member; curing the adhesive with light delivered to the adhesivevia the plurality of cavities of the proximal flange. In someembodiments, the flex circuit comprises a conductor interface extendingat an oblique angle relative to a body of the flex circuit, and whereinthe method further comprises electrically coupling a conductor to theconductor interface. In some embodiments, the method further includespositioning the conductor interface around a proximal flange of thesupport member such that the conductor is electrically coupled to theconductor interface spaced from the main body of the flex circuit. Insome embodiments, the conductor interface is spirally wrapped around theproximal flange.

In one embodiment, an intravascular imaging device is provided. Theintravascular imaging device includes a flexible elongate member sizedand shaped for insertion into a vessel of a patient, the flexibleelongate member having a proximal portion and a distal portion; animaging assembly disposed at the distal portion of the flexible elongatemember, the imaging assembly including: a flex circuit; and a supportmember around which the flex circuit is disposed, the support memberhaving a body portion including plurality of recesses, wherein thesupport member defines lumen in fluid communication with a space betweenthe flex circuit and the support member via the plurality of recesses.

In some embodiments, the support member further comprises proximal anddistal stands having a larger outer diameter than the body portion, thebody portion extending longitudinally between the proximal and distalstands; and the flex circuit is in contact with the proximal and distalstands and spaced from the body portion of support member. In someembodiments, the device further includes a backing material disposed inthe space between the flex circuit and the support member. In someembodiments, the device further includes a distal member coupled to atleast one of the flex circuit or the support member, wherein the flexcircuit and the distal member form a lap joint. In some embodiments, thesupport member comprises a distal flange sized and shaped to facilitatecoupling to the distal member. In some embodiments, the device furtherincludes a proximal member coupled to at least one of the flex circuitor the support member, wherein the flex circuit and the distal memberform a lap joint. In some embodiments, the device further includes aplurality of conductors extending along the flexible elongate member,wherein flex circuit comprises a conductor interface extending at anoblique angle relative to a body of the flex circuit, and wherein theplurality of conductors electrically coupled to the conductor interface.In some embodiments, the support member further comprises a proximalflange, wherein the conductor interface is positioned around theproximal flange such that the conductor is electrically coupled to theconductor interface spaced from the main body of the flex circuit. Insome embodiments, the conductor interface is spirally wrapped around theproximal flange.

Additional aspects, features, and advantages of the present disclosurewill become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative embodiments of the present disclosure will be describedwith reference to the accompanying drawings, of which:

FIG. 1 is a diagrammatic schematic view of an imaging system, accordingto aspects of the present disclosure.

FIG. 2 is a diagrammatic top view of a scanner assembly in a flatconfiguration, according to aspects of the present disclosure.

FIG. 3 is a diagrammatic side view of a scanner assembly in a rolledconfiguration around a support member, according to aspects of thepresent disclosure.

FIG. 4 is a diagrammatic cross-sectional side view of a distal portionof an intravascular device, according to aspects of the presentdisclosure.

FIG. 5 is a side view illustration of the intravascular device,according to aspects of the present disclosure.

FIG. 6 is a cross-sectional side view illustration of the intravasculardevice of FIG. 5.

FIG. 7 is a flow diagram of a method of assembling an intravascularimaging device, according to aspects of the present disclosure.

FIG. 8 is a perspective view illustration of a support member, accordingto aspects of the present disclosure.

FIG. 9 is a perspective view illustration of a distal portion of anintravascular device, according to aspects of the present disclosure.

FIG. 10 is a cross-sectional side view illustration of a distal portionof an intravascular device, according to aspects of the presentdisclosure.

FIG. 11 is a perspective view illustration of a distal portion of anintravascular device, according to aspects of the present disclosure.

FIG. 12 is a perspective view illustration of an intravascular device,including a distal portion of an imaging assembly, according to aspectsof the present disclosure.

FIG. 13 is a diagrammatic schematic top view of a flex circuit includinga conductor interface, according to aspects of the present disclosure.

FIG. 14 is a perspective view illustration of an intravascular device,including a distal portion of an imaging assembly, according to aspectsof the present disclosure.

FIG. 15 is a perspective view illustration of an intravascular device,including a distal portion of an imaging assembly, according to aspectsof the present disclosure.

FIG. 16 is a perspective view illustration of adhesive within anintravascular device, absent the components surrounding the adhesive,according to aspects of the present disclosure.

FIG. 17 is a cross-sectional side view illustration of an intravasculardevice, including a distal portion of an imaging assembly, according toaspects of the present disclosure.

FIG. 18 is a perspective view illustration of an intravascular device,including a distal portion of an imaging assembly, according to aspectsof the present disclosure.

FIG. 19 is a perspective view illustration of an intravascular device,including a distal portion of an imaging assembly, according to aspectsof the present disclosure.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It is nevertheless understood that no limitation tothe scope of the disclosure is intended. Any alterations and furthermodifications to the described devices, systems, and methods, and anyfurther application of the principles of the present disclosure arefully contemplated and included within the present disclosure as wouldnormally occur to one skilled in the art to which the disclosurerelates. For example, while the focusing system is described in terms ofcardiovascular imaging, it is understood that it is not intended to belimited to this application. The system is equally well suited to anyapplication requiring imaging within a confined cavity. In particular,it is fully contemplated that the features, components, and/or stepsdescribed with respect to one embodiment may be combined with thefeatures, components, and/or steps described with respect to otherembodiments of the present disclosure. For the sake of brevity, however,the numerous iterations of these combinations will not be describedseparately.

FIG. 1 is a diagrammatic schematic view of an intravascular ultrasound(IVUS) imaging system 100, according to aspects of the presentdisclosure. The IVUS imaging system 100 may include a solid-state IVUSdevice 102 such as a catheter, guide wire, or guide catheter, a patientinterface module (PIM) 104, an IVUS processing system or console 106,and a monitor 108.

At a high level, the IVUS device 102 emits ultrasonic energy from atransducer array 124 included in scanner assembly 110 mounted near adistal end of the catheter device. The ultrasonic energy is reflected bytissue structures in the medium, such as a vessel 120, surrounding thescanner assembly 110, and the ultrasound echo signals are received bythe transducer array 124. The PIM 104 transfers the received echosignals to the console or computer 106 where the ultrasound image(including the flow information) is reconstructed and displayed on themonitor 108. The console or computer 106 can include a processor and amemory. The computer or computing device 106 can be operable tofacilitate the features of the IVUS imaging system 100 described herein.For example, the processor can execute computer readable instructionsstored on the non-transitory tangible computer readable medium.

The PIM 104 facilitates communication of signals between the IVUSconsole 106 and the scanner assembly 110 included in the IVUS device102. This communication includes the steps of: (1) providing commands tointegrated circuit controller chip(s) 206A, 206B, illustrated in FIG. 2,included in the scanner assembly 110 to select the particular transducerarray element(s) to be used for transmit and receive, (2) providing thetransmit trigger signals to the integrated circuit controller chip(s)206A, 206B included in the scanner assembly 110 to activate thetransmitter circuitry to generate an electrical pulse to excite theselected transducer array element(s), and/or (3) accepting amplifiedecho signals received from the selected transducer array element(s) viaamplifiers included on the integrated circuit controller chip(s) 126 ofthe scanner assembly 110. In some embodiments, the PIM 104 performspreliminary processing of the echo data prior to relaying the data tothe console 106. In examples of such embodiments, the PIM 104 performsamplification, filtering, and/or aggregating of the data. In anembodiment, the PIM 104 also supplies high- and low-voltage DC power tosupport operation of the device 102 including circuitry within thescanner assembly 110.

The IVUS console 106 receives the echo data from the scanner assembly110 by way of the PIM 104 and processes the data to reconstruct an imageof the tissue structures in the medium surrounding the scanner assembly110. The console 106 outputs image data such that an image of the vessel120, such as a cross-sectional image of the vessel 120, is displayed onthe monitor 108. Vessel 120 may represent fluid filled or surroundedstructures, both natural and man-made. The vessel 120 may be within abody of a patient. The vessel 120 may be a blood vessel, as an artery ora vein of a patient's vascular system, including cardiac vasculature,peripheral vasculature, neural vasculature, renal vasculature, and/or orany other suitable lumen inside the body. For example, the device 102may be used to examine any number of anatomical locations and tissuetypes, including without limitation, organs including the liver, heart,kidneys, gall bladder, pancreas, lungs; ducts; intestines; nervoussystem structures including the brain, dural sac, spinal cord andperipheral nerves; the urinary tract; as well as valves within theblood, chambers or other parts of the heart, and/or other systems of thebody. In addition to natural structures, the device 102 may be may beused to examine man-made structures such as, but without limitation,heart valves, stents, shunts, filters and other devices.

In some embodiments, the IVUS device includes some features similar totraditional solid-state IVUS catheters, such as the EagleEye® catheteravailable from Volcano Corporation and those disclosed in U.S. Pat. No.7,846,101 hereby incorporated by reference in its entirety. For example,the IVUS device 102 includes the scanner assembly 110 near a distal endof the device 102 and a transmission line bundle 112 extending along thelongitudinal body of the device 102. The transmission line bundle orcable 112 can include a plurality of conductors, including one, two,three, four, five, six, seven, or more conductors 218 (FIG. 2). It isunderstood that any suitable gauge wire can be used for the conductors218. In an embodiment, the cable 112 can include a four-conductortransmission line arrangement with, e.g., 41 AWG gauge wires. In anembodiment, the cable 112 can include a seven-conductor transmissionline arrangement utilizing, e.g., 44 AWG gauge wires. In someembodiments, 43 AWG gauge wires can be used.

The transmission line bundle 112 terminates in a PIM connector 114 at aproximal end of the device 102. The PIM connector 114 electricallycouples the transmission line bundle 112 to the PIM 104 and physicallycouples the IVUS device 102 to the PIM 104. In an embodiment, the IVUSdevice 102 further includes a guide wire exit port 116. Accordingly, insome instances the IVUS device is a rapid-exchange catheter. The guidewire exit port 116 allows a guide wire 118 to be inserted towards thedistal end in order to direct the device 102 through the vessel 120.

FIG. 2 is a top view of a portion of an ultrasound scanner assembly 110according to an embodiment of the present disclosure. The assembly 110includes a transducer array 124 formed in a transducer region 204 andtransducer control logic dies 206 (including dies 206A and 206B) formedin a control region 208, with a transition region 210 disposedtherebetween. The transducer control logic dies 206 and the transducers212 are mounted on a flex circuit 214 that is shown in a flatconfiguration in FIG. 2. FIG. 3 illustrates a rolled configuration ofthe flex circuit 214. The transducer array 202 is a non-limiting exampleof a medical sensor element and/or a medical sensor element array. Thetransducer control logic dies 206 is a non-limiting example of a controlcircuit. The transducer region 204 is disposed adjacent a distal portion221 of the flex circuit 214. The control region 208 is disposed adjacentthe proximal portion 222 of the flex circuit 214. The transition region210 is disposed between the control region 208 and the transducer region204. Dimensions of the transducer region 204, the control region 208,and the transition region 210 (e.g., lengths 225, 227, 229) can vary indifferent embodiments. In some embodiments, the lengths 225, 227, 229can be substantially similar or a length 227 of the transition region210 can be greater than lengths 225, 229 of the transducer region andcontroller region, respectively. While the imaging assembly 110 isdescribed as including a flex circuit, it is understood that thetransducers and/or controllers may be arranged to form the imagingassembly 110 in other configurations, including those omitting a flexcircuit.

The transducer array 124 may include any number and type of ultrasoundtransducers 212, although for clarity only a limited number ofultrasound transducers are illustrated in FIG. 2. In an embodiment, thetransducer array 124 includes 64 individual ultrasound transducers 212.In a further embodiment, the transducer array 124 includes 32 ultrasoundtransducers 212. Other numbers are both contemplated and provided for.With respect to the types of transducers, in an embodiment, theultrasound transducers 124 are piezoelectric micromachined ultrasoundtransducers (PMUTs) fabricated on a microelectromechanical system (MEMS)substrate using a polymer piezoelectric material, for example asdisclosed in U.S. Pat. No. 6,641,540, which is hereby incorporated byreference in its entirety. In alternate embodiments, the transducerarray includes piezoelectric zirconate transducers (PZT) transducerssuch as bulk PZT transducers, capacitive micromachined ultrasoundtransducers (cMUTs), single crystal piezoelectric materials, othersuitable ultrasound transmitters and receivers, and/or combinationsthereof.

The scanner assembly 110 may include various transducer control logic,which in the illustrated embodiment is divided into discrete controllogic dies 206. In various examples, the control logic of the scannerassembly 110 performs: decoding control signals sent by the PIM 104across the cable 112, driving one or more transducers 212 to emit anultrasonic signal, selecting one or more transducers 212 to receive areflected echo of the ultrasonic signal, amplifying a signalrepresenting the received echo, and/or transmitting the signal to thePIM across the cable 112. In the illustrated embodiment, a scannerassembly 110 having 64 ultrasound transducers 212 divides the controllogic across nine control logic dies 206, of which five are shown inFIG. 2. Designs incorporating other numbers of control logic dies 206including 8, 9, 16, 17 and more are utilized in other embodiments. Ingeneral, the control logic dies 206 are characterized by the number oftransducers they are capable of driving, and exemplary control logicdies 206 drive 4, 8, and/or 16 transducers.

The control logic dies are not necessarily homogenous. In someembodiments, a single controller is designated a master control logicdie 206A and contains the communication interface for the cable 112.Accordingly, the master control circuit may include control logic thatdecodes control signals received over the cable 112, transmits controlresponses over the cable 112, amplifies echo signals, and/or transmitsthe echo signals over the cable 112. The remaining controllers are slavecontrollers 206B. The slave controllers 206B may include control logicthat drives a transducer 212 to emit an ultrasonic signal and selects atransducer 212 to receive an echo. In the depicted embodiment, themaster controller 206A does not directly control any transducers 212. Inother embodiments, the master controller 206A drives the same number oftransducers 212 as the slave controllers 206B or drives a reduced set oftransducers 212 as compared to the slave controllers 206B. In anexemplary embodiment, a single master controller 206A and eight slavecontrollers 206B are provided with eight transducers assigned to eachslave controller 206B.

The flex circuit 214, on which the transducer control logic dies 206 andthe transducers 212 are mounted, provides structural support andinterconnects for electrical coupling. The flex circuit 214 may beconstructed to include a film layer of a flexible polyimide materialsuch as KAPTON™ (trademark of DuPont). Other suitable materials includepolyester films, polyimide films, polyethylene napthalate films, orpolyetherimide films, other flexible printed semiconductor substrates aswell as products such as Upilex® (registered trademark of UbeIndustries) and TEFLON® (registered trademark of E.I. du Pont). In theflat configuration illustrated in FIG. 2, the flex circuit 214 has agenerally rectangular shape. As shown and described herein, the flexcircuit 214 is configured to be wrapped around a support member 230(FIG. 3) to form a cylindrical toroid in some instances. Therefore, thethickness of the film layer of the flex circuit 214 is generally relatedto the degree of curvature in the final assembled scanner assembly 110.In some embodiments, the film layer is between 5 μm and 100 μm, withsome particular embodiments being between 12.7 μm and 25.1 μm.

To electrically interconnect the control logic dies 206 and thetransducers 212, in an embodiment, the flex circuit 214 further includesconductive traces 216 formed on the film layer that carry signalsbetween the control logic dies 206 and the transducers 212. Inparticular, the conductive traces 216 providing communication betweenthe control logic dies 206 and the transducers 212 extend along the flexcircuit 214 within the transition region 210. In some instances, theconductive traces 216 can also facilitate electrical communicationbetween the master controller 206A and the slave controllers 206B. Theconductive traces 216 can also provide a set of conductive pads thatcontact the conductors 218 of cable 112 when the conductors 218 of thecable 112 are mechanically and electrically coupled to the flex circuit214. Suitable materials for the conductive traces 216 include copper,gold, aluminum, silver, tantalum, nickel, and tin, and may be depositedon the flex circuit 214 by processes such as sputtering, plating, andetching. In an embodiment, the flex circuit 214 includes a chromiumadhesion layer. The width and thickness of the conductive traces 216 areselected to provide proper conductivity and resilience when the flexcircuit 214 is rolled. In that regard, an exemplary range for thethickness of a conductive trace 216 and/or conductive pad is between10-50 μm. For example, in an embodiment, 20 μm conductive traces 216 areseparated by 20 μm of space. The width of a conductive trace 216 on theflex circuit 214 may be further determined by the width of the conductor218 to be coupled to the trace/pad.

The flex circuit 214 can include a conductor interface 220 in someembodiments. The conductor interface 220 can be a location of the flexcircuit 214 where the conductors 218 of the cable 114 are coupled to theflex circuit 214. For example, the bare conductors of the cable 114 areelectrically coupled to the flex circuit 214 at the conductor interface220. The conductor interface 220 can be tab extending from the main bodyof flex circuit 214. In that regard, the main body of the flex circuit214 can refer collectively to the transducer region 204, controllerregion 208, and the transition region 210. In the illustratedembodiment, the conductor interface 220 extends from the proximalportion 222 of the flex circuit 214. In other embodiments, the conductorinterface 220 is positioned at other parts of the flex circuit 214, suchas the distal portion 220, or the flex circuit 214 omits the conductorinterface 220. A value of a dimension of the tab or conductor interface220, such as a width 224, can be less than the value of a dimension ofthe main body of the flex circuit 214, such as a width 226. In someembodiments, the substrate forming the conductor interface 220 is madeof the same material(s) and/or is similarly flexible as the flex circuit214. In other embodiments, the conductor interface 220 is made ofdifferent materials and/or is comparatively more rigid than the flexcircuit 214. For example, the conductor interface 220 can be made of aplastic, thermoplastic, polymer, hard polymer, etc., includingpolyoxymethylene (e.g., DELRIN®), polyether ether ketone (PEEK), nylon,and/or other suitable materials. As described in greater detail herein,the support member 230, the flex circuit 214, the conductor interface220 and/or the conductor(s) 218 can be variously configured tofacilitate efficient manufacturing and operation of the scanner assembly110.

In some instances, the scanner assembly 110 is transitioned from a flatconfiguration (FIG. 2) to a rolled or more cylindrical configuration(FIGS. 3 and 4). For example, in some embodiments, techniques areutilized as disclosed in one or more of U.S. Pat. No. 6,776,763, titled“ULTRASONIC TRANSDUCER ARRAY AND METHOD OF MANUFACTURING THE SAME” andU.S. Pat. No. 7,226,417, titled “HIGH RESOLUTION INTRAVASCULARULTRASOUND TRANSDUCER ASSEMBLY HAVING A FLEXIBLE SUBSTRATE,” each ofwhich is hereby incorporated by reference in its entirety.

As shown in FIGS. 3 and 4, the flex circuit 214 is positioned around thesupport member 230 in the rolled configuration. FIG. 3 is a diagrammaticside view with the flex circuit 214 in the rolled configuration aroundthe support member 230, according to aspects of the present disclosure.FIG. 4 is a diagrammatic cross-sectional side view of a distal portionof the intravascular device 110, including the flex circuit 214 and thesupport member 230, according to aspects of the present disclosure.

The support member 230 can be referenced as a unibody in some instances.The support member 230 can be composed of a metallic material, such asstainless steel, or non-metallic material, such as a plastic or polymeras described in U.S. Provisional Application No. 61/985,220, “Pre-DopedSolid Substrate for Intravascular Devices,” filed Apr. 28, 2014, theentirety of which is hereby incorporated by reference herein. Thesupport member 230 can be ferrule having a distal portion 262 and aproximal portion 264. The support member 230 can define a lumen 236extending longitudinally therethrough. The lumen 236 is in communicationwith the exit port 116 and is sized and shaped to receive the guide wire118 (FIG. 1). The support member 230 can be manufactured accordingly toany suitable process. For example, the support member 230 can bemachined, such as by removing material from a blank to shape the supportmember 230, or molded, such as by an injection molding process. In someembodiments, the support member 230 may be integrally formed as aunitary structure, while in other embodiments the support member 230 maybe formed of different components, such as a ferrule and stands 242,244, that are fixedly coupled to one another.

Stands 242, 244 that extend vertically are provided at the distal andproximal portions 262, 264, respectively, of the support member 230. Thestands 242, 244 elevate and support the distal and proximal portions ofthe flex circuit 214. In that regard, portions of the flex circuit 214,such as the transducer portion 204, can be spaced from a central bodyportion of the support member 230 extending between the stands 242, 244.The stands 242, 244 can have the same outer diameter or different outerdiameters. For example, the distal stand 242 can have a larger orsmaller outer diameter than the proximal stand 244. To improve acousticperformance, any cavities between the flex circuit 214 and the surfaceof the support member 230 are filled with a backing material 246. Theliquid backing material 246 can be introduced between the flex circuit214 and the support member 230 via passageways 235 in the stands 242,244. In some embodiments, suction can be applied via the passageways 235of one of the stands 242, 244, while the liquid backing material 246 isfed between the flex circuit 214 and the support member 230 via thepassageways 235 of the other of the stands 242, 244. The backingmaterial can be cured to allow it to solidify and set. In variousembodiments, the support member 230 includes more than two stands 242,244, only one of the stands 242, 244, or neither of the stands. In thatregard the support member 230 can have an increased diameter distalportion 262 and/or increased diameter proximal portion 264 that is sizedand shaped to elevate and support the distal and/or proximal portions ofthe flex circuit 214.

The support member 230 can be substantially cylindrical in someembodiments. Other shapes of the support member 230 are alsocontemplated including geometrical, non-geometrical, symmetrical,non-symmetrical, cross-sectional profiles. Different portions thesupport member 230 can be variously shaped in other embodiments. Forexample, the proximal portion 264 can have a larger outer diameter thanthe outer diameters of the distal portion 262 or a central portionextending between the distal and proximal portions 262, 264. In someembodiments, an inner diameter of the support member 230 (e.g., thediameter of the lumen 236) can correspondingly increase or decrease asthe outer diameter changes. In other embodiments, the inner diameter ofthe support member 230 remains the same despite variations in the outerdiameter.

A proximal inner member 256 and a proximal outer member 254 are coupledto the proximal portion 264 of the support member 230. The proximalinner member 256 and/or the proximal outer member 254 can be flexibleelongate member that extend from proximal portion of the intravascular102, such as the proximal connector 114, to the imaging assembly 110.For example, the proximal inner member 256 can be received within aproximal flange 234. The proximal outer member 254 abuts and is incontact with the flex circuit 214. A distal member 252 is coupled to thedistal portion 262 of the support member 230. The distal member 252 canbe a flexible component that defines a distal most portion of theintravascular device 102. For example, the distal member 252 ispositioned around the distal flange 232. The distal member 252 can abutand be in contact with the flex circuit 214 and the stand 242. Thedistal member 252 can be the distal-most component of the intravasculardevice 102.

One or more adhesives can be disposed between various components at thedistal portion of the intravascular device 102. For example, one or moreof the flex circuit 214, the support member 230, the distal member 252,the proximal inner member 256, and/or the proximal outer member 254 canbe coupled to one another via an adhesive.

FIGS. 5 and 6 illustrate an embodiment of an intravascular device 300,including an imaging assembly 302. FIG. 5 is a side view illustration ofthe intravascular device 300. FIG. 6 is cross-sectional side viewillustration of the intravascular device 300. For clarity, the distalportion of the intravascular device 300 is shown the left side of FIGS.5 and 6, and more proximal portions are shown on the right side.

The intravascular device 300 and the imaging assembly 302 can be similarthe intravascular device 102 and the imagine assembly 110, respectively,in some aspects. The imaging assembly 302 is disposed at a distalportion of the intravascular device 300. The imaging assembly 302includes a flex circuit 314 having a transducer region 304 with aplurality of transducers 212, a controller region 308 having a pluralityof controllers, including the controller(s) 206B, and a transitionregion 310 having a plurality of conductive traces facilitatingelectrical communication between the controllers 206A, 206B and thetransducers 212.

The flex circuit 314 is positioned around the support member 330 havinga distal flange 332, a body portion 333, and a proximal flange 334. Thesupport member 330 defines a longitudinal lumen 336 that is sized andshaped to receive the guide wire 118. The flex circuit 314 is positionedin a rolled, cylindrical, and/or cylindrical toroid manner around thesupport member 330.

A distal member 352 extends distally from the support member 330 and ispositioned around the distal flange 332. The distal member 352 defines alumen 353 sized and shaped to receive the guide wire 118 and incommunication with the lumen 336 of support member 330. The distalmember 352 may be mechanically coupled to the flex circuit 314 and/orthe support member 330 via adhesive 370.

One or more proximal members 354, 356 extend proximally from the supportmember 330. For example, an outer member 354 may be positioned aroundthe proximal flange 334, and the inner member 356 may be received withinthe proximal flange 334. The inner member 356 may define a lumen 358sized and shaped to receive the guide wire 118 and in communication withthe lumen 336. The one or more proximal members 354, 356 may bemechanically coupled to the flex circuit 314 and/or the support member330 via adhesive 370.

FIG. 7 is a flow diagram of a method 400 of assembling an intravascularimaging device, including an imaging assembly with a support memberdescribed herein. It is understood that the steps of method 400 may beperformed in a different order than shown in FIG. 7, additional stepscan be provided before, during, and after the steps, and/or some of thesteps described can be replaced or eliminated in other embodiments. Thesteps of the method 400 can be carried out by a manufacturer of theintravascular imaging device.

At step 405, the method 400 includes obtaining a support member. Thesupport member includes a body portion having a plurality of recesseslongitudinally spaced from one another. The body portion can extendbetween proximal and distal stands that have a larger outer diameterthan the body portion. The support member defines longitudinal lumenextending therethrough. The body portion surrounds the lumen. Each ofthe plurality of longitudinally-spaced recesses extends from an outersurface of body portion through to an inner surface of the lumen.

At step 410, the method 400 includes positioning a flex circuit aroundthe support member. The flex circuit includes a first section having aplurality of transducers, a second section having a plurality ofcontrollers, and a third section having a plurality of conductive tracesfacilitating communication between the plurality of the transducers andthe plurality of controllers. The flex circuit can be wrapped in acylindrical configuration around the support member. The flex circuitcan be radially spaced from the body portion when positioned around thesupport member. For example, proximal and distal portions of the flexcircuit are in contact with the proximal and distal stands,respectively. A central portion of the flex circuit, between theproximal and distal portions, is radially spaced from the body portionof support member. Adhesive or other coupling mechanism may be used tojoin the flex circuit and the support member.

At step 415, the method 400 may include positioning a mandrel with thelumen of the support member. The mandrel may stabilize the supportmember during assembly of the intravascular device. In some embodiments,the mandrel may be coated and/or otherwise covered with a lubricousmaterial, such as TEFLON® (registered trademark of E.I. du Pont) and/orother suitable material.

The method 400 may additionally include positioning a plug within thelumen defined by the support member. For example, the plug may bepositioned at a proximal portion of the lumen when backing materialdirected into the lumen from the distal portion, and the plug may bepositioned at a distal portion of the lumen when backing materialdirected into the lumen from the distal portion, as described withrespect to step 420.

At step 420, the method 400 includes filling a space between the flexcircuit and the support member with a backing material. In that regard,the space between the flex circuit and support member is created whenthe flex circuit is positioned around the support member. In particular,the central portion of flex circuit is radially spaced from the bodyportion of the support member because the proximal and distal portionsof the flex circuit contact the larger diameter stands of the supportmember, when the flex circuit is wrapped or rolled around the supportmember. The backing material may be an acoustic backing material thatfacilitates operation of the transducers. The backing material may beliquid when introduced into the space between the flex circuit and thesupport member. The lumen defined by the support member may be in fluidcommunication with the space between the flex circuit and the supportmember via the plurality of recesses of the support member. Accordingly,step 420 can include introducing the backing material into the lumen ofthe support member such that the backing material flows into the spacebetween the space between the flex circuit and the support member viathe plurality of recesses. In some embodiments, the backing material maybe introduced in substantially equal proportions along the longitudinallength of the support member lumen. The recesses of the body portion ofthe support member may be axially/longitudinally and/orcircumferentially distributed to allow the backing material to evenlyfill the longitudinally length of the space between the flex circuit andthe support member. In some embodiments, backing material may bedirected into the lumen through the lumen opening at the proximalportion or the distal portion such that backing material flows into thespace between the support member and the flex circuit via the pluralityof recesses. In some embodiments, a conduit may be inserted at leastpartially into the lumen and the backing material may be directed intothe lumen and/or the space between the support member and the flexcircuit.

At step 425, the method 400 can include evacuating air from the spacebetween the flex circuit and the support member. This may advantageouslyprevent uneven filling/distribution of the backing material within thespace because of air pockets. Air may be evacuated from the space byapplying suction at one or more openings in the proximal stand and/ordistal stand of the support member. Steps 420 and 425 may be performedsimultaneously to efficiently fill the space between the flex circuitand the support member with the backing material.

At step 430, the method 400 includes removing the mandrel from thesupport member lumen after backing material cures. Because the mandrelmay be coated with a lubricous material, the mandrel may be quickly andeasily removed from the lumen.

At step 435, the method 400 includes removing excess backing materialfrom the support member lumen after the backing material cures. Becausethe liquid backing material was introduced into the space between theflex circuit and the support member through the lumen, the lumen mayinclude excess backing material. Step 435 may including reaming thesupport member lumen to remove the excess backing material which ensuresthat the internal diameter of the support member lumen is available toreceive a guide wire. Removing the excess backing material may includesliding a component having a diameter equal to or slight less than thediameter of the support member lumen through the lumen. The exertion ofthe component against the excess backing material within the lumenclears the lumen of the excess backing material. The component alsoremoves the plug which may be positioned at a proximal or distal portionof the lumen. The component used to remove the excess backing materialmay be formed of a material, such as polytetrafluoroethylene (PTFE) orTEFLON® (registered trademark of E.I. du Pont) and/or other suitablematerial, through the lumen.

The acoustic backing material cures over time. Light and/or heat may beapplied in some instances to cure the backing material.

At step 440, the method 400 includes coupling a distal member to theflex circuit and/or the support member. The support member may include adistal flange that is sized and shaped to facilitate coupling to thedistal member. When joined, a distal portion of the flex circuit mayextend over a proximal portion of the distal member such that the flexcircuit and the distal member form a lap joint. Adhesive may bepositioned between the distal member, the flex circuit, and/or thesupport member to affix the components.

At step 450, the method 400 includes electrically coupling one or moreconductors to the flex circuit. For example, the flex circuit mayinclude a conductor interface that extends at an oblique angle relativeto a body of the flex circuit. The conductive traces of the conductorinterface are in electrical communication with electronic components ofthe flex circuit, such as the controllers, transducers, and/or otherconductive traces. Electrically coupling the one or more conductorsestablishes electrical communication between the conductors and thecomponents of the flex circuit. For example, the conductors can besoldered to the conductor interface. The conductor interface can extendfrom the main body of the flex circuit such that the location on theconductor interface where the conductors are soldered is advantageouslyspaced from the main body of the flex circuit. For example, theconductor interface can be positioned around, such as in a spiral and/orother suitable configuration, around a proximal flange of the supportmember. The outer diameter of the intravascular device can beadvantageously minimized by connecting the conductor to the conductorinterface of the flex circuit spaced from the controllers and/ortransducers of the flex circuit.

At step 455, the method 400 includes coupling one or proximal members tothe flex circuit and/or the support member. For example, an inner memberand/or an outer member can be coupled to the flex circuit and/or thesupport member. In some embodiments, the inner member and outer membercan be coupled to the flex circuit and/or the support member atdifferent steps of the method 400. The support member may include aproximal flange that is sized and shaped to facilitate coupling to theproximal member(s). For example, the proximal flange may have aplurality of cavities that extends radially inwards from an outersurface of the proximal flange through the inner wall of the supportmember lumen. The inner proximal member may be positioned within theproximal flange. Step 455 can include applying adhesive to affix theinner proximal member and the support member. The adhesive may alsoadhere to the conductor interface that is positioned around the proximalflange. Light and/or heat may be delivered to the adhesive via theplurality of cavities in the proximal flange to allow curing of theadhesive. The outer proximal member may be positioned around theproximal flange. When joined, a proximal portion of the flex circuit mayextend over a distal portion of the outer proximal member such that theflex circuit and the outer proximal member form a lap joint. Adhesivemay be positioned between the one or more distal members, the flexcircuit, and/or the support member to affix the components.

FIG. 8 is perspective view illustration of an embodiment of the supportmember 330. The support member 330 is described with reference also toFIG. 10, which is a cross-sectional side view illustration of a distalportion of the intravascular device 300, including the support member330. The support member 330 may be metallic or non-metallic in variousembodiments. For example, the support member 330 may be molded plasticor polymer.

The support member 330 includes the body portion 333 extending betweenthe distal stand 342 and the proximal stand 344. The proximal and distalstands 342, 344 have a larger outer diameter than the body portion 333.The larger outer diameter of the proximal and distal stands 342, 344define a radial space 337. As described herein, when the flex circuit314 is positioned around the support member 330, the space 337 can befiled with the acoustic backing material. In that regard, the bodyportion 333 includes multiple recesses or holes 339 that are spaced fromone another. The recesses 339 may be longitudinally and/orcircumferentially distributed on the body portion 333. In that regard,the recesses 339 may be arranged in any suitable distribution or patternalong the body portion 333. In the illustrated embodiments, the recesses339 may form two spirals around the body portion 333. It is understandany suitable pattern of recesses 339, including one, two, three, four,or more spirals, a geometric pattern, such as a checkerboard, or otherregularly spaced pattern, irregular pattern, random pattern, and/orother suitable distribution may be utilized. Each of the recesses 339extends radially from an outer surface 371 of the support member throughan inner wall 372 of the lumen 336. The recesses 339 establish fluidcommunication between the lumen 336 extending longitudinally through thesupport member and the space 337. The space 337 may be filled with theacoustic backing material by introducing the backing material into thelumen such that the backing material flows in the space 337 through therecesses 339. In that regard, the recesses 339 may be distributed and/orspaced from one another such that the backing material evenly fills thespace 337. Recesses 339 may have any suitable shape, including a circle(as shown), polygon, ellipse, etc.

In the illustrated embodiment, the stand 342 includes an opening 343.The opening 343 extends longitudinally between proximal and distal sidesof the stand 342. When the space 337 is filled with the backingmaterial, suction may be applied at the opening 343 to evacuate any airin the space 337. While only one opening 343 is shown, it is understoodmore than one opening 343 may be provided on the stand 342. In otherembodiments, opening(s) 343 may be provided only on the proximal stand344 and/or both the proximal and distal stands 342, 344.

The support member 330 includes the distal flange 332. In variousembodiments, the inner diameter and/or outer diameter of the distalflange 332 may be larger than, smaller than, and/or equal to the innerdiameter and/or outer diameter of the central portion 333. In anexemplary embodiment, the inner and outer diameters of the distal flange332 are substantially equal to the inner and outer diameters of the bodyportion 333. The distal flange 332 may be sized and shaped to facilitatecoupling with the distal member 352. In that regard, the distal flange332 may have cross-sectional profile that is straight/linear, tapered,spiral groove-shaped, screw thread-shaped, buttress thread-shaped,and/or otherwise suitably shaped, including the shapes described in U.S.Provisional App. No. 62/315,395, filed Mar. 30, 2016, the entirety ofwhich is hereby incorporated by reference herein. As shown in FIG. 10,the distal flange 332 engages an inner surface 355 of a lumen 353 of thedistal member 352 when the distal member 352 is positioned around thedistal flange. The spiral groove or buttress thread shape of the distalflange 332 in the illustrated embodiment advantageously enhancesadhesion and/or grip by increasing the surface area of contact betweenthe support member 330 and the distal member 352. This advantageouslyresults in higher pull strength values required to separate the supportmember 330 and the distal member 352. In some embodiments, the adhesive370 may be positioned the flex 314, the support member 330, and/or thedistal member 352 to support the coupling.

FIGS. 9, 10, and 11 illustrate an embodiment of the distal portion ofthe intravascular device 300 where the flex circuit 314, the supportmember 330, and/or the distal member 352 are mechanically coupled to oneanother. FIGS. 9 and 11 are perspective view illustrations of the distalportion of the intravascular device 300, including the imaging assembly302. FIG. 9 shows a relatively earlier stage of the assembly process forthe intravascular device 300, while FIG. 11 shows a relatively laterstage. FIG. 10 is a cross-sectional side view illustration of theintravascular device 300, including the imaging assembly 302.

As shown in FIGS. 9 and 10, a distal portion 321 of the flex circuit 314overlaps a proximal portion 359 of the distal member 352 to form a lapjoint 357. Conventional intravascular devices utilized butt jointsencapsulated by a fillet that undesirably increases the outer diameterof the intravascular device. The lap joint 357 may be advantageouslyimplemented with adhesive 370 to minimize the outer diameter, such as toachieve a 3 F or smaller outer diameter for the intravascular device300. When the intravascular device 300 is assembled, the proximalportion 359 of the distal member 352 can be coated with the adhesive370, and the distal member 352 can be moved proximally and slide underdistal portion 321 of the flex circuit 314. The adhesive 370mechanically affixes one or more of the distal member 352, the supportmember 330, and/or the flex circuit 314 to one another. The distalmember 352 can be slide proximally over and around the distal flange 352such that the distal member 352 abuts distal stand 352. As illustratedin FIG. 11, the adhesive 370 can also be applied around the joint 357.The joint 357 advantageously creates and maintains a hermetic seal forthe flex circuit 314. In some embodiments, the lap joint 357 can beformed when the proximal portion 359 of the distal member 352 overlapsthe distal portion 321 of the flex circuit 314.

Referring again to FIG. 8, the support member 330 includes a proximalflange 334. The proximal flange 334 may be sized and shaped tofacilitate coupling to one or more proximal members 354, 356. In variousembodiments, the inner and/or outer diameter of the proximal flange 334may be larger than, smaller than, and/or equal to the inner and/or outerdiameter of the central portion 333. In an exemplary embodiment, theinner and outer diameters of the proximal flange 334 are larger than theinner and outer diameters of the central portion 333. The proximalflange 334 includes a plurality of cavities 341. As described herein,the cavities 341 can facilities adhesion between the proximal members354, 356, the flex circuit 314, and/or the support member 330 with theadhesive 370.

FIGS. 12 and 14-19 illustrate various steps in assembly of theintravascular device 300. In particular, FIGS. 12 and 14-19 showcomponents of the intravascular device 300 at a proximal portion of theimaging assembly 302. FIGS. 12, 14, 15, 18, and 19 are perspective viewillustrations of the imaging assembly 302. FIG. 16 is cross-sectionalside view illustration of the imaging assembly 302.

The flex circuit 314 includes a conductor interface 320. The conductorinterface 320 extends proximally from a proximal portion 322 of the flexcircuit 314. One or more conductors 218 of the cable 112 (FIGS. 1 and 2)are electrically coupled to the conductor interface 320. For example,the conductors 218 can be soldered at a proximal portion 323 of theconductor interface 320. By electrically coupling the conductors 218 atthe distal portion 323 of the conductor interface 320, the conductors218 can be soldered at a location spaced from the electronic componentsin the main body of the flex circuit 414. This may advantageouslyminimize the outer diameter of the imaging assembly 302 and theintravascular device 300 because the thickness associated with solderingthe conductors is moved away from the flex circuit 314. The conductorinterface 320 includes conductive traces that are in electricalcommunication with the flex circuit 314. Electrically coupling theconductors 218 to the conductor interface 320 thus facilitates exchangeof electrical signals between the conductors 218, the controllers 206A,206B, and/or the transducers 212 (FIGS. 2 and 6). The conductorinterface 320 extends at an oblique angle relative to a main body of theflex circuit 314. The main body of the flex circuit 314 can collectivelydescribe the transducer region 310, the controller region 308, and thetransition region 310.

FIG. 13 is a diagrammatic schematic top view of a flex circuit 414 and aconductor interface 420. The conductor interface 420 forms an obliqueangle α with respect to the main body of the flex circuit 414. Theoblique angle α may be between approximately 0° and approximately 89° insome embodiments. The oblique angle may be between approximately 91° andapproximately 179° in some embodiments. The proximal portion 423includes conductive pads 417 where the conductors 218 are soldered. Theconductive pads 417 are in electrical communication with the conductivetraces 215, which are, in turn, in electrical communication with theelectronic components of the flex circuit 414.

As shown in FIGS. 12 and 14, the conductor interface 320 can bepositioned around the proximal flange 334. For example, the conductorinterface 320 can be wrapped in a spiral or helical configuration aroundthe proximal flange 334. The conductor interface 320 can be wound aroundthe proximal flange 334 any suitable number of times, depending on thelength of the conductor interface 320. In other embodiments, theconductor interface 320 can extend proximally from the main body of theflex circuit in a different manner, such as a linear/straightconfiguration, a curved configuration, etc.

The flex circuit 314, the support member 330, and/or the proximalmembers 354, 356 are coupled with the adhesive 370 at the proximal joint379. FIG. 14 illustrates that the inner proximal member 356 can beinserted into and received within the proximal flange 334. The conductorinterface 320 may be wrapped in a spiral configuration around both theproximal flange 334 and the inner member 356 in some embodiments. Insuch embodiments, the conductors 218 can extend along the length of theintravascular device 300 within a lumen of the outer member 354, betweenthe inner member 356 and the outer member 354.

The adhesive 370 is applied onto and around the proximal flange 334, asillustrated in FIG. 15-17. The adhesive 370 flows through the cavities341 of the proximal flange 334 so that the adhesive 370 covers surfacesof the inner member 356 and the support member 330. The cavities 341 arelongitudinally and/or circumferentially distributed on the proximalflange 334. Each of the cavities 341 extends radially from an outersurface 376 of the proximal flange 334 through an inner wall 377 of thelumen 336. As described above, in some embodiments, the inner diameterof the lumen 336 may be larger in proximal flange than in the centralportion 333. The cavities 341 establish fluid communication betweenspaces of the intravascular device above/outside (e.g., between theouter member 354 and the proximal flange 334) and below/inside (e.g.,within the lumen 336, between the proximal flange 334 and the innermember 356) of the proximal flange 334. In that regard, the cavities 341may be distributed and/or spaced from one another such that the adhesive370 evenly coats the support member 330, the flex circuit 314, and/orthe proximal member 354, 356. The cavities 341 may have any suitableshape, including oblong (as shown), circle, polygon, ellipse, etc. Thecavities 341 advantageously allow for light to travel to penetrate theproximal flange 334 and cure the adhesive 370.

FIG. 16 illustrates a stylized shape that the adhesive 370 assumes whenthe proximal portion of the imaging assembly 302 is coated with theadhesive 370. The structural components of the intravascular device 300are not visible in FIG. 15. The pillars 373 of the adhesive 370 extendwithin the cavities 341 of the proximal flange 334. The pillars 373 areformed between an outer circumference 374 and an inner circumference375. The inner circumference 375 establishes adhesive contact betweenthe proximal flange 334 and the inner member 356. The outercircumference 374 establishes adhesive contact between the proximalflange 334 and the outer member 354. The pillars 373 extending throughthe cavities 341 establishes continuity between the outer and innercircumferences 374, 375 and strengthens the bond between the supportmember 330 and the proximal members 354, 356.

As shown in FIGS. 17-19, the outer member 354 can be moved distally overand around the proximal flange 334 and the conductor interface 320 untilthe outer member 354 abuts the proximal stand 344. The proximal joint379 can be a lap joint, which can advantageously seal the flex circuit314 using the adhesive 370. For example, a distal portion 378 canoverlap a proximal portion 322 b in some embodiments. In suchembodiments, the proximal portion 322 b may be bent and secured to theproximal flange 334, allowing the outer member 354 to slide over theproximal portion 322 b. In other embodiments, a proximal portion 322 aof the flex circuit 314 overlaps the outer member 354. In suchembodiments, the distal portion 378 of the outer member may be slidunderneath the proximal portion 322 a. The distal portion 378 and/or theproximal portion 322 a, 322 b may be coated with the adhesive 370. Asillustrated in FIG. 19, the adhesive 370 can also be applied around thejoint 379.

Various embodiments of an intravascular device and/or imaging assemblycan include features described in U.S. Provisional App. No. 62/315,395,filed on Mar. 30, 2016, U.S. Provisional App. No. 62/315,406, filed onMar. 30, 2016, U.S. Provisional App. No. 62/315,421, filed on Mar. 30,2016, and U.S. Provisional App. No. 62/315,416, filed on Mar. 30, 2016,the entireties of which are hereby incorporated by reference herein.

Persons skilled in the art will recognize that the apparatus, systems,and methods described above can be modified in various ways.Accordingly, persons of ordinary skill in the art will appreciate thatthe embodiments encompassed by the present disclosure are not limited tothe particular exemplary embodiments described above. In that regard,although illustrative embodiments have been shown and described, a widerange of modification, change, and substitution is contemplated in theforegoing disclosure. It is understood that such variations may be madeto the foregoing without departing from the scope of the presentdisclosure. Accordingly, it is appropriate that the appended claims beconstrued broadly and in a manner consistent with the presentdisclosure.

What is claimed is:
 1. A method of assembling an intravascular imagingdevice, the method comprising: obtaining a support member comprising abody portion including a plurality of recesses longitudinally spacedfrom one another; positioning a flex circuit around the support membersuch that the flex circuit is radially spaced from the body portion ofthe support member; and filling a space between the flex circuit and thesupport member with a backing material through the plurality of recessesof the body portion, wherein the support member defines a lumen in fluidcommunication with the space between the flex circuit and the supportmember via the plurality of recesses.
 2. The method of claim 1, whereinthe filling includes introducing the backing material into the lumen ofthe support member such that the backing material flows into the spacebetween the flex circuit and the support member via the plurality ofrecesses.
 3. The method of claim 2, further comprising: positioning amandrel within the lumen before filing the space between the flexcircuit and the support member with the blacking material; and removingthe mandrel after the backing material cures.
 4. The method of claim 2,further comprising: removing excess backing material from the lumenafter the backing material cures.
 5. The method of claim 1, wherein eachof the plurality of recesses extends from an outer surface of bodyportion through an inner surface of the lumen.
 6. The method of claim 1,wherein the body portion of the support member surrounds the lumen. 7.The method of claim 1, wherein the support member includes proximal anddistal stands, the body portion extending longitudinally between theproximal and distal stands, and wherein the proximal and distal standshave a larger outer diameter than the body portion.
 8. The method ofclaim 7, wherein the positioning a flex circuit around the supportmember includes wrapping the flex circuit in a cylindrical configurationaround the support member such that the flex circuit is in contact withthe proximal and distal stands and spaced from the body portion ofsupport member.
 9. The method of claim 7, further comprising: evacuatingair from the space between the flex circuit and the support member viaan opening in at least one of the proximal or distal stands.
 10. Themethod of claim 1, further comprising: coupling a distal member to atleast one of the flex circuit or the support member.
 11. The method ofclaim 10, wherein the flex circuit and the distal member form a lapjoint.
 12. The method of claim 10, wherein the support member includes adistal flange sized and shaped to facilitate coupling to the distalmember.
 13. The method of claim 1, further comprising: coupling aproximal member to at least one of the flex circuit or the supportmember.
 14. The method of claim 13, wherein the flex circuit and thedistal member form a lap joint.
 15. The method of claim 13, wherein thesupport member includes a proximal flange having a plurality ofcavities, and wherein the coupling a proximal member comprises: applyingan adhesive to affix the proximal member and the support member; curingthe adhesive with light delivered to the adhesive via the plurality ofcavities of the proximal flange.
 16. The method of claim 14, wherein theflex circuit comprises a conductor interface extending at an obliqueangle relative to a body of the flex circuit, and wherein the methodfurther comprises electrically coupling a conductor to the conductorinterface.
 17. The method of claim 16, further comprising: positioningthe conductor interface around a proximal flange of the support membersuch that the conductor is electrically coupled to the conductorinterface spaced from the main body of the flex circuit.
 18. The methodof claim 17, wherein the conductor interface is spirally wrapped aroundthe proximal flange.
 19. An intravascular imaging device comprising: aflexible elongate member sized and shaped for insertion into a vessel ofa patient, the flexible elongate member comprising a proximal portionand a distal portion; an imaging assembly disposed at the distal portionof the flexible elongate member, the imaging assembly including: a flexcircuit; and a support member around which the flex circuit is disposed,the support member comprising a body portion including plurality ofrecesses, wherein the support member defines a lumen in fluidcommunication with a space between the flex circuit and the supportmember via the plurality of recesses, wherein the lumen and theplurality of recesses are configured to allow a backing material to fillthe space between the flex circuit and the support member.
 20. Thedevice of claim 19, wherein the support member further comprisesproximal and distal stands comprising a larger outer diameter than thebody portion, the body portion extending longitudinally between theproximal and distal stands; and the flex circuit is in contact with theproximal and distal stands and spaced from the body portion of supportmember.
 21. The device of claim 20, wherein the backing materialdisposed in the space between the flex circuit and the support member.22. The device of claim 19, further comprising: a distal member coupledto at least one of the flex circuit or the support member, wherein theflex circuit and the distal member form a lap joint.
 23. The device ofclaim 22, wherein the support member comprises a distal flange sized andshaped to facilitate coupling to the distal member.
 24. The device ofclaim 19, further comprising: a proximal member coupled to at least oneof the flex circuit or the support member, wherein the flex circuit andthe distal member form a lap joint.
 25. The device of claim 19, furthercomprising a plurality of conductors extending along the flexibleelongate member, wherein flex circuit comprises a conductor interfaceextending at an oblique angle relative to a body of the flex circuit,and wherein the plurality of conductors electrically coupled to theconductor interface.
 26. The device of claim 25, wherein the supportmember further comprises a proximal flange, wherein the conductorinterface is positioned around the proximal flange such that theconductor is electrically coupled to the conductor interface spaced fromthe main body of the flex circuit.
 27. The device of claim 26, whereinthe conductor interface is spirally wrapped around the proximal flange.